This invention relates to a cable bush mounted on a cable and, in particular, to a method for mounting the cable bush (bushing) on the cable which is used for connecting between a mobile antenna unit for receiving a digital radio broadcasting and a receiver (receiver body) and which has a skin coated with a slippery material.
In recent years, a digital radio receiver, which receives a satellite wave or a terrestrial wave to listen the digital radio broadcasting, has been developed and is put to practical use in the United States of America. The digital radio receiver is mounted on a mobile station such as an automobile and can receive an electric wave having a frequency of about 2.3 gigahertz (GHz) to listen in a radio broadcasting. That is, the digital radio receiver is a radio receiver which can listen in a mobile broadcasting. Inasmuch as the received wave has the frequency of about 2.3 GHz, a reception wavelength (resonance wavelength) λ thereof is equal to about 128.3 mm. In addition, the terrestrial wave is an electric wave in which a signal where the satellite wave is received in an earth station is frequency shifted a little.
Inasmuch as the electric wave having the frequency of about 2.3 GHz is used in the digital radio broadcasting in the manner which is described above, it is necessary to set up an antenna outside the automobile. Accordingly, the antenna must be attached to a roof of the automobile in a case where the digital radio receiver is mounted in the automobile.
Such as an antenna for the automobile and a receiver (receiver body) put inside a room of the automobile are electrically connected to each other through a cable. On mounting the cable to the antenna for the automobile, it is necessary to hold one end portion of the cable in the antenna. For this purpose, the cable is mounted with a cable bush. The cable bush is also called a bushing.
The cable has a skin coated with a slippery material such as polytetrafluoroethylene or PTFE. In other words, the cable has a slippery skin. The bushing is made of polyvinyl chloride or PVC. Therefore, adhesion between the bushing and the cable is poor. When the cable is pulled, the bushing may slide on the skin of the cable thereby the bushing may shift on the cable. As a result, it is desired to mount the bushing on the cable with the bushing securely fixed to the cable.